Efficient Support for Workspace-Local Queries in a Repository That Supports File Versioning

1. A method, implemented on a processor, comprising the steps of: maintaining, separate from a database table, a plurality of mappings; wherein the database table contains a plurality of records; wherein each mapping of the plurality of mappings corresponds to a different workspace of a plurality of workspaces; wherein each mapping of the plurality of mappings explicitly indicates which records, within the database table, are associated with the workspace to which said each mapping corresponds; receiving a first request, associated with a first workspace, for one or more records from the database table; in response to receiving the first request: accessing, from the plurality of mappings, a first mapping that is associated with the first workspace; determining, from the first mapping, which records in the database table are associated with the first workspace; and returning first information only from the records determined to be associated with the first workspace; receiving a second request, associated with a second workspace that is a different workspace from the first workspace, for one or more records from the database table; in response to receiving the second request: accessing, from the plurality of mappings, a second mapping that is associated with the second workspace and that is a different mapping from the first mapping; determining, from the second mapping, which records in the database table are associated with the second workspace; and returning second information only from the records determined to be associated with the second workspace; wherein at least one of the records determined to be associated with the first workspace is the same record as a record determined to be associated with the second workspace.

2. The method of claim 1 , wherein the step of receiving a request includes receiving a request that identifies the first workspace.

3. The method of claim 2 , wherein the step of receiving a first request includes receiving a first request that identifies a particular database table, and wherein the step of accessing a first mapping includes accessing a first mapping that is associated with the particular database table.

4. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 3 .

5. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 2 .

6. The method of claim 1 , wherein the first mapping is a bit vector in which each bit corresponds to a record identifier that identifies a particular row in the database table.

7. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 6 .

8. The method of claim 1 , wherein the step of returning first information includes returning a respective memory location at which each of the records, determined to be associated with the first workspace, are persistently stored.

9. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 8 .

10. The method of claim 1 , wherein the step of returning first information includes returning respective content of each of the records determined to be associated with the first workspace.

11. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 10 .

12. The method of claim 1 , wherein the database table contains records corresponding to respective versions of resources stored in a repository that supports versioning.

13. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 12 .

14. The method of claim 1 , wherein the database table contains records coffesponding to respective content of XML elements from one or more XML documents.

15. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 14 .

16. The method of claim 1 , further comprising the steps of: determining from the first request that the database table identified in the first request contains records associated with the plurality of workspaces; and rewriting the query to include a particular operator through which a routine is invoked, wherein execution of the routine causes the steps of accessing and determining to be performed.

17. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 16 .

18. The method of claim 1 , wherein the step of receiving a first request includes receiving a SQL statement that includes the first request.

19. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 18 .

20. The method of claim 1 , wherein at least one of the records determined to be associated with the first workspace is not a record determined to be associated with the second workspace.

21. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 20 .

22. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 1 .

23. A method, implemented on a processor, comprising the steps of: maintaining, separate from a database table, a plurality of mappings; wherein the database table contains a plurality of records; wherein each mapping of the plurality of mappings corresponds to a different workspace of a plurality of workspaces; wherein each mapping of the plurality of mappings explicitly indicates which records, within the database table, are associated with the workspace to which said each mapping corresponds; receiving a first request, associated with a first workspace, for one or more records from the database table; in response to receiving the first request: accessing, from the plurality of mappings, a first mapping that is associated with the first workspace; determining, from the first mapping, whether each of one or more records in the database table is associated with the first workspace; and returning first information that indicates whether each of the one or more records is associated with the first workspace; receiving a second request, associated with a second workspace that is a different workspace from the first workspace, for one or more records from the database table; in response to receiving the second request: accessing a second mapping that is associated with the second workspace and that is a different mapping from the first mapping, wherein the second mapping indicates which records in the database table are associated with the second workspace; determining, from the second mapping, whether each of the one or more records in the database table is associated with the second workspace; and returning second information that indicates whether each of the one or more records in the database table is associated with the second workspace; wherein at least one of the records determined to be associated with the first workspace is the same record as a record determined to be associated with the second workspace.

24. The method of claim 23 , wherein the step of receiving a first request includes receiving a first request that identifies the first workspace.

25. The method of claim 24 , wherein the step of receiving a first request includes receiving a first request that identifies a particular database table, and wherein the step of accessing a first mapping includes accessing a first mapping that is associated with the particular database table.

26. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 25 .

27. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 24 .

28. The method of claim 23 , wherein the first mapping is a bit vector in which each bit corresponds to a record identifier that identifies a particular row in the database table.

29. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 28 .

30. The method of claim 23 , wherein the database table contains records corresponding to respective versions of resources stored in a repository that supports versioning.

31. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 30 .

32. The method of claim 23 , wherein the database table contains records coffesponding to respective content of XML elements from one or more XML documents.

33. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 32 .

34. The method of claim 23 , further comprising the steps of: determining from the first request that the database table identified in the first request contains records associated with the plurality of workspaces; and rewriting the query to include a particular operator through which a routine is invoked, wherein execution of the routine causes the steps of accessing and determining to be performed.

35. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 34 .

36. The method of claim 23 , wherein the step of receiving a first request includes receiving a SQL statement that includes the first request.

37. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 36 .

38. The method of claim 23 , wherein at least one of the records determined to be associated with the first workspace is not a record determined to be associated with the second workspace.

39. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 38 .

40. A machine-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the steps of claim 23 .